Wave Bubble 2010 - Design by Mictronics

USB and Battery Charger board

Here is a short description of the USB and Battery Charger board for my Wave Bubble 2010.

Due to hardly available parts on Digikey the battery charging circuit was modified and uses now an LTC1730-4.2
LiPo charger IC.
The LTC1730-4.2 handles charging of a single LiPo cell and includes overcurrent and overtemperature protection
for the battery. The board connects through a mini-USB connector either to a PC for data transfer or to a
wall adapter for charging.
Charging current depends on the external power supply but overcurrent protection is set to 2A.
A green LED will indicate charging status.

USB data transfer is handled by a simple USB-RS232 converter, the FT232L.

Errata

Hints & Testing

Populating the board should be a big deal, double check the FT232RL for bad soldering.

To test the serial connection just short the RX and TX line on the main board connector and send something through your terminal, the characters will be echoed back.

To check the LiPo charger connect a current meter between one battery terminal and the board. Depending on the charging level you should see a continuous current, or in trickle charge mode an intermittent current. Heat the temperature sensor in the middle of the board with a soldering iron, charging should stop immediately and continue after short cool down.